In order to establish authority and trust on social media it's very important to write a professional sounding bio for your profiles. When someone finds your account and is deciding whether or not to start following you and whether or not to follow your suggestions to buy X product, one of the first things they will do is to check your profile and to see what you're all about. They will then make up their mind on this based almost entirely on your bio so you better make sure it sounds professional and compelling.
How do you ensure that it is?
Professional vs Personal
If this is a business account and you're trying to attract customers, network or otherwise build yourself a reputation then you should make sure to use a professional tone. That means avoiding flippant remarks, using professional terms and checking your spelling and grammar. Just a little personal thrown in for good measure won't hurt though remember that social media is personal in nature.
Make sure you avoid using lots of jargon and buzz words. Your objective is not to sound clever here; you want to be clear and precise about what it is that you do and not dress it up with buzzwords like 'synergy', 'integration', 'emerging markets'. Less is more, so be frugal with your use of words and use short sentences especially if there's a word limit.
Think About Your Audience
If you're still having a hard time finding your 'tone' then imagine a prototypical person you are marketing to. Maybe you even know someone in real life who fits into the right demographic. Keep them in mind then imagine you're writing directly to them.
Don't Repeat Yourself
If this is LinkedIn, then you'll have a chance to show your accomplishments later on. If it's Facebook, you can include details about your business in other sections. This should be an overview that is efficient in telling people who you are. Efficiency means avoiding covering ground that will be addressed later.
Still struggling? Don't worry, not everyone is a born writer and that's fine. Just make sure that if you don't have that natural 'voice' that you don't just 'make do' with what you've got. Hiring a professional to write your bio shouldn't be expensive and it will result in a much more professional sounding and engaging experience for your visitors.